Frost plug heater

Abstract

The clamping mechanism for securing in place an electric heating element insertable through a frost plug aperture into the coolant passage in the blocks of a water cooled internal combustion engine includes a screw having a head located on the outside of a removable body member carrying the heating element, which body member is adapted to be inserted into the apertures to sealingly close it against leakage. The inner end of the screw extends freely through an opening formed in a bight portion connecting a pair of opposed side walls of a rigid yoke having a length greater than the largest dimension of the aperture and adapted to engage the inner surface of the block around the aperture and is threaded into a nut loosely captivated within the yoke by the bight portion, side walls and detents extending inwardly from the side walls and overlying the bight portion. The yoke opening is so sized and the detents are so arranged that the rigid yoke may be tilted about the screw to enter the block through the aperture. The screw head is shaped to be engageable by a socket driven by a power tool, such as an electric or pneumatic screw driver, for rotating the screw to tighten the clamping means during assembly of the immersion heating element into the engine block.

What is claimed is: 
     
       1. In an electric immersion heater for heating liquid in a container having an aperture in a wall thereof, said heater including a disc shaped body member adapted to close the aperture and having an electric immersion heater element mounted thereto, the body member having means adapted to engage the outer surface of the container around the aperture, as well as clamping means including a rigid yoke having a length longer than the longest dimension of the aperture and being adapted to be engageable with the inner surface of the container adjacent the aperture for clamping the body member to the container so that it closes the aperture and the heater element extends through the aperture into the container, the improvement wherein the clamping means comprises a screw having a head, said head being configured to be received by a conventional socket in an automatic rotating tool, the screw passing through a bore in the body member such that the head is located on the outside thereof, the inner end of the screw extending loosely through an opening in the yoke of the clamping means, the opening having a larger diameter that the diameter of the screw, a nut threadably secured to the screw between the yoke and the inner end of the screw, said yoke cooperating with the nut for preventing rotation of the nut during rotation of the screw during assembly, and wherein said yoke includes two opposed side walls connected by a bight portion, the yoke further including detent means extending from at least one of said side walls over the bight portion, said nut being loosely capitavitively positioned between said side walls, bight portion and detent means thereby maintaining the nut within the confines of the yoke, said detent means being spaced a sufficient distance from the bight portion and nut, and detent means being so arranged with respect to the inner end of the screw, and said yoke opening being of such size to permit the yoke to be tilted about the screw to enter the container aperture during assembly, with the head configuration and outside location facilitating easy assembly by an operator using a rotating tool to engage the head for rotating the screw to tighten the clamping means. 
     
     
       2. The improvement of claim 1 wherein the nut has opposite sides thereof dimensioned to be slightly smaller than the distance between the side walls of the yoke whereby abutment of the nut sides against the yoke walls prevents rotation of the nut. 
     
     
       3. The improvement of claim 2 wherein the body member bore is sufficiently large to permit the screw to slide therein. 
     
     
       4. The improvement of claim 3 wherein the diameter of the yoke opening is greater than that of the bore in the body member. 
     
     
       5. The improvement of claim 4 wherein said body member is an integral piece of metal having a thickness in excess of 1/8 inch. 
     
     
       6. A frost plug heater for heating coolant contained in an engine block having an aperture therein, said heater comprising: a solid metallic disc shaped body member having a thickness between major faces of at least 1/8 inch, the body member being adapted to close the engine block aperture and including a peripheral portion adapted to engage the outer surface of the engine block around the aperture said disc carrying a heating element, a bore extending through the major faces of said body member, a screw extending through the bore and having a head located on the outside of the body member adapted to be received by a socket in a rotating machine; a rigid yoke having an opening through which the inner end of the screw loosely extends and a length larger than the largest dimension of the aperture in the engine block and engageable with the interior surface of the engine block around the aperture, said yoke having a pair of opposed side walls connected by a bight portion, the yoke further including detent means extending from at least one of the yoke side walls over the bight portion, a nut threadably secured to the screw and loosely captivatively located within the confines of said yoke between said bight portion, detent means and side walls; said detent means being spaced a sufficient distance from the bight portion, said detent means being so arranged with respect to the inner end of the screw, and the opening in the yoke through which the screw extends being of such size to permit the yoke to be tilted about the screw to enter the engine block aperture during assembly while restricting the degree of maximum tilt of the yoke, with the nut sides being dimensioned to be slightly smaller than the distance between the side walls of the yoke whereby abutment of the nut sides against the yoke walls prevents rotation of the nut, and all of the dimensions of the head as viewed from the screw axis being smaller than the dimensions of the nut, and the head being smaller than the nut and being selected from the group of hex washer, recessed hex, cross round, slotted round, cross pan and slotted pan heads whereby the rotating machine socket can easily obtain access to the relatively small head.   
     
     
       7. The heater of claim 6 wherein the yoke includes an opening larger in diameter than the bore and wherein said detent means comprises a pair of detents located on opposite sides of the yoke opening.